ZDZ Super 80 Mid-range
I have a ZDZ Super 80 with header and canister muffler (From RC Showcase) and a 24x12 composite 3-blade propeller. I just changed out the Tennison carb with a Walbro carb, but I'm still having some mid-range issues. A group of us tried adjusting both the low speed and high speed needles, but could not smooth out the midrange. I've been told, by friends, that to either shorten the header, or shorten the exhaust tube (which is original and still kind of long) coming out the back of the canister muffler. But prior to doing any cutting, which we don't know would fix or cause more problems, I thought I would ask for HELP!.
I got an email reply from Mike
With the TR-80, you MUST use the wraparound header at its full length. DO NOT SHORTEN IT.
We use this setup with the 26x12 2 blade and get 6400rpm.
The 24x12 should be close.
The silencer must be getting cooled sufficiently to work properly as well.
Please look at tell me what carb is installed on the engine.
I hope it is a Walbro WJ71.
Let me know.